Conventional golf balls can be divided into two general classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material, and a cover. It is also possible to surround a hollow or fluid-filled center with a plurality of solid layers. Solid balls have traditionally been considered longer and more durable than wound balls, but many solid constructions lack the “feel” provided by the wound construction.
More recently, by altering ball construction and composition, manufacturers have been able to vary a wide range of playing characteristics, such as compression, velocity, “feel,” and spin, optimizing each or all be optimized for various playing abilities. In particular, a variety of core and cover layer(s) constructions, such as multi-layer balls having dual cover layers and/or dual core layers, have been investigated and now allow many non-wound balls to exhibit characteristics previously maintainable in a solid-construction golf ball. These golf ball core and cover layers are typically constructed with a number of polymeric compositions and blends, including polybutadiene rubbers, polyurethanes, polyureas, polyamides, and, specifically, ethylene-based ionomers.
Most of the aforementioned compositions and constructions are configured to produce a golf ball that is within the performance limits set by the United States Golf Association (“USGA”) that regulate tournament golf. Recreational players, however, are not required to play golf balls that fall within the USGA limits.
The Rules of Golf, as approved by the USGA, include the following rules that relate to golf ball construction:                a. Weight—the weight of the ball shall not be greater than 1.620 oz.        b. Size—the diameter of the ball shall be not less than 1.680 in. This specification will be satisfied if, under its own weight, a ball falls through a 1.680-in-diameter ring gauge in fewer than 25 out of 100 randomly selected positions, the test being carried out at a temperature of 23±1° C.        c. Spherical Symmetry—the ball must not be designed, manufactured or intentionally modified to have properties which differ from those of a spherically symmetrical ball.        d. Initial Velocity—the velocity of the ball shall not be greater than 250 ft/s when measured on apparatus approved by the USGA. A maximum tolerance of 2% will be allowed. The temperature of the ball when tested will be 23±1° C.        e. Overall Distance Standard (“ODS”)—a brand of golf ball, when tested on apparatus approved by the USGA on the outdoor range at the USGA Headquarters under the conditions set forth in the ODS for golf balls on file with the USGA, shall not cover an average distance in carry and roll exceeding 280±16.8 yd.        
The Initial Velocity rule test is well known. The test is conducted by conditioning a ball for a minimum of 3 hr at 23±1° C. The room in which the test is to be conducted is conditioned to 23±2° C. The ball is then struck by a striking mass of approximately 250 lb at a striker velocity of 143.8 ft/s.
The ODS test for golf balls is conducted by striking the golf ball with a golf club having a lie angle of 55±2°; a swing weight of D2±1; a loft of 11±10°; a weight of 13.3±1 oz; a vibrational frequency of 4.6±0.3 Hz, a moment of inertia of 162±30 oz-in; a club length of 43.5±20 inches; a laminated head construction, a cycolac insert, a dynamic still steel shaft, and an all-weather rubber grip. The clubhead velocity during the ODS test is about 160±0.5 ft/s measured at the hosel of the club over the last 4 inches of travel prior to impact. The distance traveled is adjusted for zero wind and an ambient temperature of 75° F.
The flight of a golf ball is determined by many factors, but only three factors are typically controlled by the golfer. By impacting the ball with a golf club, the golfer typically controls the speed of the golf ball, the launch angle, and the spin rate. The launch angle sets the initial trajectory of the golf balls flight. The speed and spin of the ball give the ball lift which will define the balls overall flight path along with the weight and drag of the golf ball. Where the ball stops after being struck by a golf club also depends greatly on the weather and the landing surface the ball contacts.
Many golfers have a low swing speed. This means that the club head speed at impact is relatively slow when compared to that of a professional golfer. Typically, when driving a golf ball, the average professional golf ball speed is approximately 234 ft/s (160 mph). A person having a low swing speed typically drives the ball at a speed less than 176 ft/s (120 mph). Upwards of thirty percent of all golfers today have swing speeds that produce drives of less than 210 yards. A person with a low swing speed has a low ball speed and, as a result, the golf ball does not fly very far because of the lack of speed and lift.
In the past, low weight golf balls have been suggested to help improve distance for low swing speed players. Low weight golf balls, however, slow down faster than do conventional golf balls due to drag. Changes in the diameter of golf balls has also been experimented with. Old British golf balls (balls made before the USGA rules were adopted by the Royal and Ancient Golf Club of St. Andrews, Scotland) were typically made with a diameter of 1.620 inches.
As such, there is a need, therefore, for non-conforming golf balls that are formed from a variety of compositions and constructions and, in particular, ionomer compositions that are neutralized at high percentages. The present invention describes such compositions and there use in a variety of golf ball core and cover layers.